What’s in a name…

Unprecedented warming and the ‘Hockey Stick’ controversy

Current global change at unprecedented rates

Review: Enhancing the greenhouse gas effect

Dutch Elfstedentocht: February 1985

NOAA: climate at a glance

How warm has is gotten? (Ed Hawkins)

http://blogs.reading.ac.uk/climate-lab-book/files/2020/05/spiral_2020_large.gif


  • Globe: combined land and ocean-surface temperature was 0.93 of a degree C above the 20th-century average for July


  • Northern Hemisphere: land-surface temperature was the highest ever recorded for July, 1.54 degrees C above average


  • Asia had its hottest July on record, Europe had its second-hottest July and North America, South America, Africa and Oceania all had a top-10 warmest July

Physical impacts of climate change

Last decade reveals smallest sea ice extents

Haber-Bosch process (1909) and human population

Greenhouse gases (ice cores)

Greenhouse gases: Carbon dioxide (CO2)

Global Change and Water are intimately linked


Global Change: Fresh Water Scarcity

Global Change: Ocean acidification

Global Change: Sea Level Rise

Paris Climate Agreement


  • Accord between nation in UN to address climate change


  • Goal to keep increase in global temperature below 2 °C
    • pursue efforts to limit increase to 1.5
    • pursue net zero emissions


  • Contributions by country determined by that country
    • no emissions targets or dates
    • must go beyond current efforts
    • framework for transparency

Are targets of the Paris Climate Agreement reachable?

What should we do….



  • If CO2 emissions stopped today:
    • 50% absorbed by land/water in 30 yrs
    • 30% in atmosphere for centuries
    • 20% in atmosphere for 1000 yrs


  • Future warming is inevitable
    • land sinks uncertain
    • ocean sinks weakening


  • Negative emissions techology?